Superconducting transitions of the (Yb, Lu, Sc)Ba2Cu3O7-y systems

[[abstract]]In the rare earth barium copper oxide system Ba2Cu3O7-y, almost all compounds show superconductivity above 90 K (R=Y, La, Nd, Sm, Eu, Gd, Dy, Ho, Er, Tm, Yb, Lu, Th). However, no YBa2Cu3O7-type phase or superconductivity was observed in ScBa2Cu3O7. Whether this is due to smaller ionic radius of the Sc3+ ion (0.73 angstrom) or difficult sample preparation condition is not clear. In orde to check these possibilities, we study two pseudoquaternary systems (Yb1-xScx)Ba2Cu3O7-y and (Lu1-xScx)Ba2Cu3O7-y where ionic radii of Yb3+ (0.86 angstrom) and Lu3+ (0.85 angstrom) are closer to Sc3+ ion. Superconducting properties of these two systems from electrical and magnetic measurements as well as crystallographic properties will be discussed in detail.[[fileno]]2010102010205[[department]]物理